This proposal builds on an established multicenter research collaboration to develop a large cohort of injured pediatric patients that can be analyzed to categorize the types of mechanisms of injury children sustain, to determined which mechanism of injury criteria are the most accurate for identifying children who need the resources of a trauma center, and to identify the best criteria for determining when a trauma team should meet an injured child in the emergency department (i.e., trauma team activation). Importance: This information will be used to ensure that severely injured children receive the most appropriate care, decreasing morbidity and mortality, while at the same time conserving limited resources and minimizing costs. Specific Aims: 1) Categorize and describe the mechanisms of injury sustained by injured pediatric patients transported by emergency medical services, because the mechanism of injury categories currently used are not sufficient for evaluating pediatric patients and need to be better defined and perhaps expanded. 2) Identify the mechanisms of injury that are associated with severe injury and the need for the resources of a trauma center. 3) Identify which prehospital criteria are the most accurate for identifying children whose injuries require trauma team activation prior to their arrival at the emergency department. Study Design: A prospective, 36-month observational study will be conducted. The prehospital emergency medical service provider in charge of each child's care prior to their arrival at the emergency department will complete an interview on the condition of the patient at the scene of their injury and the patient's mechanism of injury. After the patient is discharged from the hospital or emergency department, their treatments and outcome will be abstracted from their medical record. These data will be used to analyze how to categorize mechanisms of injury for children and what mechanism of injury information best identifies injured children who need a trauma center. All of the prehospital data will also be analyzed to determine what combination of data best identifies those children for whom a trauma team should be activated prior to their arrival at the emergency department. Setting: The study will be conducted at the children's hospitals in Milwaukee, WI; Rochester, NY; and Dallas, TX. Participants: All pediatric patients transported by emergency medical services to one of the three participating hospitals for an injury, regardless of severity, will be included. Interventions: This study will use emergency medical service interviews and medical record reviews to gather data. Outcome Measures: The primary outcome for determining which children need a trauma center will be a composite measure of whether or not the child had urgent non-orthopedic surgery within 24 hours of arrival, admission to an intensive care unit, and/or death. The primary outcome for determining which children need a trauma team activation will be placement of a surgical airway, cesarean section, thoracotomy, non-orthopedic surgery, or death within four hours of arriving at the trauma center.